title: The neural substrate of spectral preference in Drosophila.
abstract: Drosophila vision is mediated by inputs from three types of photoreceptor neurons; R1-R6 mediate achromatic motion detection, while R7 and R8 constitute two chromatic channels. Neural circuits for processing chromatic information are not known. Here, we identified the first-order interneurons downstream of the chromatic channels. Serial EM revealed that small-field projection neurons Tm5 and Tm9 receive direct synaptic input from R7 and R8, respectively, and indirect input from R1-R6, qualifying them to function as color-opponent neurons. Wide-field Dm8 amacrine neurons receive input from 13-16 UV-sensing R7s and provide output to projection neurons. Using a combinatorial expression system to manipulate activity in different neuron subtypes, we determined that Dm8 neurons are necessary and sufficient for flies to exhibit phototaxis toward ultraviolet instead of green light. We propose that Dm8 sacrifices spatial resolution for sensitivity by relaying signals from multiple R7s to projection neurons, which then provide output to higher visual centers.
authors.affiliation: Unit on Neuronal Connectivity, Laboratory of Gene Regulation and Development, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
authors.forename: Shuying
authors.initials: S
authors.lastname: Gao
authors.forename: Shin-Ya
authors.initials: SY
authors.lastname: Takemura
authors.forename: Chun-Yuan
authors.initials: CY
authors.lastname: Ting
authors.forename: Songling
authors.initials: S
authors.lastname: Huang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Lu
authors.forename: Haojiang
authors.initials: H
authors.lastname: Luan
authors.forename: Jens
authors.initials: J
authors.lastname: Rister
authors.forename: Andreas S
authors.initials: AS
authors.lastname: Thum
authors.forename: Meiluen
authors.initials: M
authors.lastname: Yang
authors.forename: Sung-Tae
authors.initials: ST
authors.lastname: Hong
authors.forename: Jing W
authors.initials: JW
authors.lastname: Wang
authors.forename: Ward F
authors.initials: WF
authors.lastname: Odenwald
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: White
authors.forename: Ian A
authors.initials: IA
authors.lastname: Meinertzhagen
authors.forename: Chi-Hon
authors.initials: CH
authors.lastname: Lee
mesh_terms: D025042:Amacrine Cells / Q000166:cytology / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D055253:Color Vision / Q000502:physiology* / Q000528:radiation effects; D054910:Compound Eye, Arthropod / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects; D004331:Drosophila melanogaster / Q000166:cytology / Q000502:physiology*; D007395:Interneurons / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects; D055537:Light Signal Transduction / Q000502:physiology / Q000528:radiation effects; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000502:physiology; D010775:Photic Stimulation; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects; D013569:Synapses / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology / Q000528:radiation effects; D014466:Ultraviolet Rays; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects